Filter-press plate.



No. 675,589. Patented Jun 4, I90I.

. H. F. CLEVELAND.

FILTER PRESS PLATE.

(Application filed July 1.3, 1900.)

(No Model.)

WE'hwmaex. 152m? 7250? 1-4:. 0mm vzrcns co, Marianna, wunmm'on, n c.

llarrrnn Srarns PATENT OFFICE.

HARRY I CLEVELAND, OF VINOENNES, INDIANA, ASSIGNOR TO THE TURNEY DRIERCOMPANY, OF CHICAGO, ILLINOIS.

lFlL'l'ER PRESS PLATE.

SJPIEGMEIGAIIQN forming part of Letters Eatent N0. 67' 5,589, dated June4, 1901.

Application filed July 18, 1900. Serial No. 23,432- (No model.)

To all whom it may concern:

Be it known that I, HARRY F. CLEVELAND, a citizen of the United States,residing at Vincennes, county of Knox, State of Indiana, have inventedcertain new and useful Improvements in Filter-Press Plates, of which thefollowing is a specification, reference being had to the accompanyingdrawings, forming a part thereof.

In the drawings, Figure 1 is an elevation of my improved filter-pressplate, having a portion of its perforated outer covering broken away,uncovering an open-meshed wovenwire screen underneath the same, andhaving a portion of said screen broken away, uncovering the groovedcentral or back element. Fig. 2 is a detail section of the same, upon anenlarged scale, at the line .2 2 on Fig. 1.

In filter-presses of the type employing filtering-plates of the generalcharacter of my invention such filtering-plates have hitherto generallybeen provided with a surface covering or filtering element of wovenfabric, (canvas or the like,) such fabric being mounted upon a centralor back element having grooves or channels into which the liquid passeswhen forced through the filtering fabric which covers its surface. Suchgrooves have suitable drainagepassages by which the liquid is carriedoff. The woven fabric employed in such presses and as the filteringelement of the filter-plates, which forms the walls of the cells,rapidly deteriorates with use, and a large item of the cost ofmaintaining such presses consists in the cost of replacing suchfiltering-cloth from time to time. My present invention consists in thesubstitution of finely-perforated sheet metal for such cloth.

My improved filter-plate comprises a central or back element A, which ispreferably a plank, grooved up and down on both surfaces when it is tobe used as the intermediate wall between two cells, the grooves beingconnected at the lower edge or margin of the plate by a cross-channel Awhich leads to a dischargeduct- A by which the liquid is conducted outof the press. Upon this grooved surface of the plank there is firstplaced a woven-wire screen I3, which is secured by staples or otherconvenient means. Outside of the woven-Wire screen I apply theperforated sheet-metal plate 0, which constitutes the filtering element.On account of the greater freedom with which the water passes throughthis perforated sheet metal than through the filtering-cloth usuallyemployed only a portion of the surface of the grooved plate need becovered by the perforated metal in order to obtain as rapid results aswhen the entire plate is covered with the filtering fabric. I make theperforated metal plate O, therefore, to constitute only a band or stripacross the middle portion of the height of the grooved back element A,covering the remaining portion above and below the perforated plate withimperforate sheet-metal plates D D. The central or back element A hasthe induction-aperture A at the center, the drainage grooves or channelsbeing interrupted so that they do not reach said induction-aperture,leaving an un grooved surface around the margin of the latter. Both thewoven-wire screenB and the perforated plate C have a correspondingaperture, that in the woven wire being considerably larger, so that themargin of the aperture does not nearly reach the margin of the apertureA; but the aperture 0 in the perforated plate C is only slightly largerthan the aperture A, so that the margin of said aperture 0 laps onto theungrooved surface of the plank A around the aperture A and is theresecured by tacks or in any other convenient manner. Both the perforatedplate 0 and the imperforate plates D D are secured to the plank A attheir outer periphery by nails or tacks beyond the ends of thedrainage-grooves, and the lateral edgesthat is, the upper and loweredges-of the plate C and the abutting edges of the plates D D aresimilarly secured by tacks taking through the meshes of the woven wireinto the ribs be tween the channels or grooves of the plank A.

The filter-plates of the structure indicated are assembled in cells inthe customary manner of construction of presses of this class. Theperipheral cell-wall, as shown at E in Fig. 2, seats on the plank A,beyond the periphery of the perforated and imperforate plates 0 and D,and all the plates of the press are bound together by strain-rodsF Finthe customary manner.

For the perforated plate 0, I prefer to use quite thin metal, and themost efficient operation and the most rapid filtration for a given areamay be obtained when the perforations are elongated, as shown in Fig. 1,though I have also employed sheet metal having circular perforations.

The perforated sheet-metal plate 0 should have its perforations assmoothly cut as possible, avoiding ragged edges, by which solid materialmight be retained in the perforations, causing them to become entirelyclosed, for it will be understood that the filtration effected in theuse of this plate is not caused primarily by the fact that the aperturesin the plate are too small to allow solid matter to pass, but by reasonof the accumulation across the apertures, in a manner abridging them, ofsolid particles sufficiently large to be thus lodged and serve thispurpose, such particles of bran or fiber eventually constituting a filmwhich completely bridges the apertures and becomes itself the filteringmeans through which only the clear liquid can pass, leaving all finersolid matter behind. If the particles instead of being thus lodgedacross the slots become wedged into them they are eventually closed.When a plate of this construction is first put into usethat is, when thecell is first filled with the matter to be filtered before theaccumulation of particles constituting a film over the apertures, asabove described, has occurred sufficiently to answer that purpose-theliquor passes through, containing a large portion of solid matter whichis desired to eX- tract. It is therefore important to hasten theaccumulation of the filtering -'film or bridgeover the apertures, andfor the purpose above stated it is desirable to use elongated aperturesor slots rather than round apertures in order to increase the area openfor filtration and also because the individual round apertures are moreliable to become filled up than the longer ones. If, however, theperforated plate is applied with the elongated apertures having theirlength up and down, the current of water passing through them with adownward trend tends to slide the particles which might accumulate onthe surface of the plate at the entering side down along the apertures,and thus prevent the apertures from being rapidly covered entirely bythe film, which would hold-back the finer particles and make thefiltration perfect. I prefer, therefore, to place the perforated sheetwith the elongated apertures extended horizontally, as shown in thedrawings.

I claim- 1. A filtering-plate for a filter-press, comprising a back orcentral element superficially channeled or grooved, and a surfacecovering for the same constituting the sole filtering element,consisting of sheet metal finely perfoments together.

rated and secured outside the grooved surface of the back or centralelement, and forming the outer surface of the plate.

2. A filtering-plate for a filter-press, comprising a back or centralelement superficially channeled or grooved; an open-meshed wire screenapplied on the grooved surface of said back element; a perforatedsheet-metal plate applied on the screen; and constituting the outersurface and the sole filtering element of the plate and means forbinding said ele- 3. A filtering-plate for a filter-press, coniprising aback or central element superficially channeled or grooved, having anaperture for supplying the material to be filtered within the peripheryof such channeled or grooved portion; and a surface coveringconstituting the sole filtering element, consisting of finely-'perforated sheet metal applied outside the grooved surface of the backor central element forming the outer surface of the plate, and having anaperture corresponding to the supply-aperture of said grooved element,the grooves of the latter being interrupted so that they do notextend'to said central aperture; said perforated sheet-metal elementbeing secured to the grooved element at the un grooved surface of saidelement around the aperture, and also at the periphery of suchperforated sheet metal.

4:. A filtering-plate for a filter-press, comprising a back or centralelement superficially channeled or grooved and having an aperture forsupplying the material to be filtered within the periphery of suchchanneled or grooved portion; and a surface covering constituting thesole filtering element, consisting of a perforated sheetmetal plateapplied over the grooved surface of the back or central element formingthe outer surface of the plate; and suitable means for binding suchsheetmetal plate to the grooved element beyond the ends of the grooves.

5. A filtering-plate for a filter-press, com- I prising a back orcentral element having vertical parallel channels or grooves in itssurface, and means for draining the same; and a surface covering,constituting the filtering element, of a strip or band of perforatedsheet metal, extending across the vertical grooves in the middle portionof the height of the plate, and an imperforate surface covering for theupper and lower portions of the grooved plate; and suitable means forbinding both the perforated and the imperforate coverings to the groovedplate at their margins respectively.

6. A filtering-plate for a filter-press, comprising a back or centralelement superficially channeled or grooved, and a surface covering forthe same, constituting the filtering element, consisting of sheet metalperforated with elongated slots, the same being applied to the groovedplate with the length of slots horizontal.

7. A filtering-plate for a filter-press, comprising a back or centralelement having ver- In testimony whereof I have hereunto set ticalarallel channels or rooves and suit- In hand at Vincennes Indiana in theres- 10 able means for draining the same at the lower ence of twoWitnesses, this 7th day of July, end; and a surface coveringfor thesame, con- A. D. 1900.

stituting the filtering element, consisting of HARRY F. CLEVELAND.perforated sheet metal Whose perforations are Attest:

extended or elongated in a direction trans- F. F. BAKER,

verse to the grooves in the back element. T. P. LAIN.

